My thoughts:
-The visuals, music, and characters (cards) are great. The cards are varied and very charming.
-It would be nice to have a preview of what cards do before summoning. However, experimenting with card interactions is fun and rewarding when you find a new combination.
-Due to the nature of the engine, the levels are more like puzzles than a dynamic card game. Both puzzle and dynamic styles can have their merits, but sometimes a puzzle format can be frustrating when it feels like you're just grinding to find the one way to win.